The present invention relates to waste treatment apparatus and more particularly to waste treatment apparatus for use in the sterilisation of infectious and/or quarantined waste. However, it will be appreciated that the invention is not limited to that particular use and will find application in treating other types of waste which require sterilisation.
Hospitals produce a large amount of infectious and/or quarantined waste. Generally, most hospitals have a number of infectious waste collection bins dispersed throughout the various wards and departments. These waste bins are periodically collected and removed to an off-site waste treatment facility for chemical sterilisation or high-temperature incineration of the waste, followed by sterilisation of the bin itself. This is an expensive process which suffers from many disadvantages.
One such disadvantage is the risk of environmental damage during the transport of infectious waste over public roads. In addition, the building and operation of an off-site chemical or incineration treatment centre represents a high capital cost outlay and requires expensive chemicals and/or fuels for operation.
It is an object of the present invention, at least in its preferred embodiment, to overcome or at least ameliorate one or more of the above prior art disadvantages.
Accordingly to one aspect of the invention there is provided a waste treatment apparatus comprising:
a first sealable chamber for containing untreated waste, the chamber having therein a cutting mechanism and vents through which steam may be introduced under pressure.
In other preferred embodiment, the device further comprises a grate adjacent to the cutting mechanism through which treated waste is ejected from the first chamber.
In another embodiment of the invention, the first chamber further includes an advance mechanism for urging the waste against the cutting mechanism.
In other embodiments there is provided a pivoting hopper for depositing untreated waste into the first chamber. There is concurrently provided a transport for inverting a bin over the hopper.
In some embodiments there is also provided a bin cleaning mechanism located beneath the hopper.
In some preferred embodiments a second sealable chamber in which waste deposited from the first chamber is treated.
In other embodiments of the invention, a third chamber is interposed between the first and second chambers and comprises an isolation gate valve for separating the first and second chambers.
In other embodiments of the invention, either the first or the second chambers are provided with external jackets carrying steam to heat the respective chambers.
There is also disclosed means for collecting both the liquid and vapour discharges of the treatment chambers.
In particular embodiments, the cutting mechanism comprises a gearbox carrying two or more rotating cutting heads.
In some preferred embodiments, the gearbox is a planetary gearbox and the gearbox rotates within the first chamber.
In one form of the invention, the apparatus is mounted on the back of a truck or trailer to facilitate transporting from site to site. The truck or trailer can supply all the power requirements of the device, including electric, hydraulic, gas and/or pressurised steam.
In another form of the invention, the apparatus is produced as an on-site plant.
According to another aspect of the invention there is provide a method of treating waste comprising the steps of:
(i) introducing untreated waste into a sealable chamber,
(ii) shredding the waste in the chamber and simultaneously applying steam to the waste to thereby sterilise the waste, and
(iii) discharging the shredded, sterilised waste from the chamber.
In some preferred methods of the invention, the shredded, sterilised waste is discharged into a second sealable chamber where the waste is subjected to further treatment.
In preferred embodiments of the invention, the waste in the second chamber is subjected to further steam treatment.
In other preferred embodiments of the invention, the method further comprises the steps of collecting liquid waste discharged during the process and sterilising it separately prior to disposal.
In one embodiment, the method also includes evacuating all air and/or gas from the chamber prior to steps (ii) and (iii) and decontaminated through a multi-stage active carbon filter or the like.